1 /*-
2 * Copyright (c) 2010 Isilon Systems, Inc.
3 * Copyright (c) 2010 iX Systems, Inc.
4 * Copyright (c) 2010 Panasas, Inc.
5 * Copyright (c) 2013-2017 Mellanox Technologies, Ltd.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice unmodified, this list of conditions, and the following
13 * disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29 #ifndef _LINUXKPI_LINUX_SPINLOCK_H_
30 #define _LINUXKPI_LINUX_SPINLOCK_H_
31
32 #include <asm/atomic.h>
33 #include <sys/param.h>
34 #include <sys/kernel.h>
35 #include <sys/lock.h>
36 #include <sys/mutex.h>
37 #include <sys/kdb.h>
38
39 #include <linux/cleanup.h>
40 #include <linux/compiler.h>
41 #include <linux/rwlock.h>
42 #include <linux/bottom_half.h>
43 #include <linux/lockdep.h>
44
45 typedef struct mtx spinlock_t;
46
47 /*
48 * By defining CONFIG_SPIN_SKIP LinuxKPI spinlocks and asserts will be
49 * skipped during panic(). By default it is disabled due to
50 * performance reasons.
51 */
52 #ifdef CONFIG_SPIN_SKIP
53 #define SPIN_SKIP(void) unlikely(SCHEDULER_STOPPED() || kdb_active)
54 #else
55 #define SPIN_SKIP(void) 0
56 #endif
57
58 #define spin_lock(_l) do { \
59 if (SPIN_SKIP()) \
60 break; \
61 mtx_lock(_l); \
62 local_bh_disable(); \
63 } while (0)
64
65 #define spin_lock_bh(_l) do { \
66 spin_lock(_l); \
67 local_bh_disable(); \
68 } while (0)
69
70 #define spin_lock_irq(_l) do { \
71 spin_lock(_l); \
72 } while (0)
73
74 #define spin_unlock(_l) do { \
75 if (SPIN_SKIP()) \
76 break; \
77 local_bh_enable(); \
78 mtx_unlock(_l); \
79 } while (0)
80
81 #define spin_unlock_bh(_l) do { \
82 local_bh_enable(); \
83 spin_unlock(_l); \
84 } while (0)
85
86 #define spin_unlock_irq(_l) do { \
87 spin_unlock(_l); \
88 } while (0)
89
90 #define spin_trylock(_l) ({ \
91 int __ret; \
92 if (SPIN_SKIP()) { \
93 __ret = 1; \
94 } else { \
95 __ret = mtx_trylock(_l); \
96 if (likely(__ret != 0)) \
97 local_bh_disable(); \
98 } \
99 __ret; \
100 })
101
102 #define spin_trylock_irq(_l) \
103 spin_trylock(_l)
104
105 #define spin_trylock_irqsave(_l, flags) ({ \
106 (flags) = 0; \
107 spin_trylock(_l); \
108 })
109
110 #define spin_lock_nested(_l, _n) do { \
111 if (SPIN_SKIP()) \
112 break; \
113 mtx_lock_flags(_l, MTX_DUPOK); \
114 local_bh_disable(); \
115 } while (0)
116
117 #define spin_lock_irqsave(_l, flags) do { \
118 (flags) = 0; \
119 spin_lock(_l); \
120 } while (0)
121
122 #define spin_lock_irqsave_nested(_l, flags, _n) do { \
123 (flags) = 0; \
124 spin_lock_nested(_l, _n); \
125 } while (0)
126
127 #define spin_unlock_irqrestore(_l, flags) do { \
128 (void)(flags); \
129 spin_unlock(_l); \
130 } while (0)
131
132 #ifdef WITNESS_ALL
133 /* NOTE: the maximum WITNESS name is 64 chars */
134 #define __spin_lock_name(name, file, line) \
135 (((const char *){file ":" #line "-" name}) + \
136 (sizeof(file) > 16 ? sizeof(file) - 16 : 0))
137 #else
138 #define __spin_lock_name(name, file, line) name
139 #endif
140 #define _spin_lock_name(...) __spin_lock_name(__VA_ARGS__)
141 #define spin_lock_name(name) _spin_lock_name(name, __FILE__, __LINE__)
142
143 #define spin_lock_init(lock) mtx_init(lock, spin_lock_name("lnxspin"), \
144 NULL, MTX_DEF | MTX_NOWITNESS | MTX_NEW)
145
146 #define spin_lock_destroy(_l) mtx_destroy(_l)
147
148 #define DEFINE_SPINLOCK(lock) \
149 spinlock_t lock; \
150 MTX_SYSINIT(lock, &lock, spin_lock_name("lnxspin"), MTX_DEF)
151
152 #define assert_spin_locked(_l) do { \
153 if (SPIN_SKIP()) \
154 break; \
155 mtx_assert(_l, MA_OWNED); \
156 } while (0)
157
158 #define local_irq_save(flags) do { \
159 (flags) = 0; \
160 } while (0)
161
162 #define local_irq_restore(flags) do { \
163 (void)(flags); \
164 } while (0)
165
166 #define atomic_dec_and_lock_irqsave(cnt, lock, flags) \
167 _atomic_dec_and_lock_irqsave(cnt, lock, &(flags))
168 static inline int
_atomic_dec_and_lock_irqsave(atomic_t * cnt,spinlock_t * lock,unsigned long * flags)169 _atomic_dec_and_lock_irqsave(atomic_t *cnt, spinlock_t *lock,
170 unsigned long *flags)
171 {
172 if (atomic_add_unless(cnt, -1, 1))
173 return (0);
174
175 spin_lock_irqsave(lock, *flags);
176 if (atomic_dec_and_test(cnt))
177 return (1);
178 spin_unlock_irqrestore(lock, *flags);
179 return (0);
180 }
181
182 /*
183 * struct raw_spinlock
184 */
185
186 typedef struct raw_spinlock {
187 struct mtx lock;
188 } raw_spinlock_t;
189
190 #define raw_spin_lock_init(rlock) \
191 mtx_init(&(rlock)->lock, spin_lock_name("lnxspin_raw"), \
192 NULL, MTX_DEF | MTX_NOWITNESS | MTX_NEW)
193
194 #define raw_spin_lock(rl) spin_lock(&(rl)->lock)
195 #define raw_spin_trylock(rl) spin_trylock(&(rl)->lock)
196 #define raw_spin_unlock(rl) spin_unlock(&(rl)->lock)
197
198 #define raw_spin_lock_irqsave(rl, f) spin_lock_irqsave(&(rl)->lock, (f))
199 #define raw_spin_trylock_irqsave(rl, f) spin_trylock_irqsave(&(rl)->lock, (f))
200 #define raw_spin_unlock_irqrestore(rl, f) spin_unlock_irqrestore(&(rl)->lock, (f))
201
202 /*
203 * cleanup.h related pre-defined cases.
204 */
205 DEFINE_LOCK_GUARD_1(spinlock_irqsave,
206 spinlock_t,
207 spin_lock_irqsave(_T->lock, _T->flags),
208 spin_unlock_irqrestore(_T->lock, _T->flags),
209 unsigned long flags)
210
211 #endif /* _LINUXKPI_LINUX_SPINLOCK_H_ */
212